Figure 7
From: From the scala naturae to the symbiogenetic and dynamic tree of life
Symbiogenesis, natural selection, and the dynamic Earth as key processes that caused biological evolution. The Last Universal Common Ancestor (LUCA) evolved into the earliest self-replicating proto-cells (ancient microbes) ca. 4000 to 3500 million years ago. Over the subsequent eons, these archaic microbes evolved into numerous bacterial ecotypes that today inhabit every micro-niche where organic molecules (or light) are available. Moreover, these micro-organisms gave rise to larger, eukaryotic cells via symbiogenesis (primary endosymbiosis). These nucleated cells further evolved into multicellular organisms, such as algae, fungi, animals and plants.